Throwing karmas which cause a particular rebirth.Completing karmas which determine the circumstances(including length) of life.

Throwing karmas, which picks your parents, are taught in conjunction with the 12 dependent arisings (of rebirth). It is a complicated teaching.

There are also other practices called phowas for vajrayana practitioners to incur a fortunate rebirth in general or also specifically to choose the exact parents while inhabiting a "bardo" body. This second method is called ejecting the consciousness and is part of a larger system that encompasses the Highest Yoga tantras.

If there is a radical inconsistency between your statements and the position you claim to hold,you are a sock puppet.Make as many accounts as you want; people can identify your deception with this test.

"The concept of karmic connection is very important in Buddhism especially in the human development. Karma binds the relationships between body/minds; it is the power of the reunification of mind and matter, child and parents. The accumulated karma of the past life establishes the karmic connection with one’s future life and fortune, and directs the consciousness towards the future parents. Without a karmic connection, even with qualified energy of the couple and favorable conditions, the conception will not take place".